If you're not a power trainer don't bother with him. It'll do you 1 or 2 seasons more than a regular 5* player from the transfer list, and, with the tokens it costs you can easly buy 4 or 5 5* players.

If you are a power trainer, and are looking for fast trainers, then they are not cheap but they are granted and train very fast, so you'll be able to keep them at top levels for several seasons.